chore(deps-dev): bump typescript from 3.8.3 to 3.9.6

Bumps [typescript](https://github.com/Microsoft/TypeScript) from 3.8.3 to 3.9.6.
- [Release notes](https://github.com/Microsoft/TypeScript/releases)
- [Commits](microsoft/TypeScript@v3.8.3...v3.9.6)

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -68,7 +68,7 @@
     "standard-version": "^8.0.0",
     "ts-jest": "^26.1.1",
     "tslint": "^6.1.2",
-    "typescript": "^3.8.3"
+    "typescript": "^3.9.6"
   },
   "dependencies": {
     "@types/body-parser": "^1.17.1",